Tricyclic antipsychotics discovery

Tricyclic antidepressants—so called because of the characteristic three-ring nucleus—have been used clinically for four decades (Figure 30-1). They closely resemble the phenothiazines chemically and, to a lesser extent, pharmacologically. Like the latter drugs, they were first thought to be useful as antihistamines with sedative properties and later as antipsychotics. The discovery of their antidepressant properties was a fortuitous clinical observation. Imipramine and amitriptyline are the prototypical drugs of the class as mixed norepinephrine and serotonin uptake inhibitors though they also have several other properties. 

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